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Sketch of common septic system component setbacks and clearances. Septic Tank & Field Clearance Distances to Water Wells etc.
Required Septic Isolation Distances from Wells, Streams, Trees, etc.

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Clearances or isolation distances for septic tank, drainfield, soakaway bed, & wells:

Septic tank or field setbacks & clearances for septic systems to wells, buildings, property lines, & distances to other site features. Well setbacks & clearances to septics, property lines, buildings, etc.

. In this article a detailed septic distances table describes distance requirements between septic components (septic tank, leach field, cesspools, drywells) and other site features such as wells, water supply piping, streams, trees, property boundaries, lakes, etc.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Online Tables of Required Septic Setbacks & Clearance Distances

Photograph of a swimming pool installed too close to a septic drainfield - in failure (C) Daniel Friedman

[Click to enlarge any image]

In general, septic effluent must be disposed of on the property from which it originates.

However more strict clearances and distances than this are required between various onsite wastewater treatment system components and buildings, property boundaries, lakes, streams, wells, and so on, as detailed in the table below. Contact us with corrections or additions to this data.

These septic component clearance distance tables below give distance requirements between septic components and wells, streams, trees, property boundaries, lakes, etc.

Common guidelines require at least 50' clearance distance between a well and a septic system tank or 150' between a well and a septic drainfield or leaching bed but you will see that different authorities may recommend different distances.

Local soil and rock conditions can make these "rules of thumb" unreliable. See "One and Two Family Dwelling Code, Section P-2510-Combined Seepage Pits and Disposal Fields," and Table P-2504, "Location of Sewage Disposal System." Other references are cited at the end of this table.

Article Contents

Table 1 Septic System Component Clearance Distances (in feet) from Wells, Buildings, & Other Site Features

Site Feature / Component  (below)

Sewer Line
Distance
Septic D-Box
Septic Tank Distance

 SEPTIC TANK LOCATION
Drainfield
Distance

SEPTIC DRAINFIELD
LOCATION
Other Sanitary Code Specifications General

SEPTIC COMPONENT LOCATIONS
MASSACHUSETTS
TITLE 5
 

Authority or Model Code

General /
TYPICAL6
General General /
TYPICAL
 
General /
TYPICAL
 
FL
Florida
MA Title 5
Massachusetts
NY
New York
More
Information
Cistern 25   25 25 - - - CISTERNS
Drainfield, Soakbed, Soil Absorption System above high groundwater (water table) or "depth to groundwater"     4 - 5 ft. to > 10 ft.   - - 4 ft

SEPTIC DRAINFIELD SHAPE

Allowable depth from bottom of soakbed trenches to seasonal high groundwater level must be greater in coarse gravely soil and may be as little as 5 ft. in fine soils passing the #200 sieve test. 8-1

Drainfield, Soil Absorption Sys. Minimum Area     150   - - - -
Drainfield, SAS Other exc repair area     20   - - - -
Dry gulch 10     256.2        
Embankment top or
Cuts >= 2ft hgt
    20   - - - -
Intercept drain
up-slope
    10   - - - -
Intercept drain
down-slope
    26   - - - -
Lake, watercourse, stream, wetland
[high water line]
50 100 75

100 6.2

50 OH10

75 ft 50 - -
Neighboring residence 5   200   - -- -
Property Line 10 10 10

10

50 OH10

10 5   NEIGHBORING SEPTIC SYSTEM PROBLEMS
Septic Tank cover soil backfill
min" - max"
    6"-?"   - 12"-24" - -
Sinkhole or drainage well       300 OH10      

Reduced to 100 ft if a permanent vegetative buffer is maintained around the sinkhole or drainage well

SINKHOLES & SUBSIDENCES

Surficial Sinkhole Edges     500   - - - -
Spring 50   50

100

2006.1 .2 .4

- - - -
Structures to Septic Tank / Leach field
[Occupied]
  20

5 - general
10 MO
15 bsmt-MO

20 5 ft 8 ft - -
Structures to Sewer Line
[Occupied]
5   2          
Subsoil drain line 10   10 25        
Swimming Pool     15-MO   - - - SEPTIC to POOL DISTANCE
Trees, large     10   - ? - PLANTS & TREES OVER SEPTIC SYSTEMS
Water supply piping
[Potable]
10   10 25 10 -- -
Water Supply Piping
under suction
50   50

100

2006.1 .2 .4

- -- -

Water well, Private, or well suction line
[Potable]

25 (cast iron)
or
50 other
100 50

10010

2006.1 .2 .4

75 10050

WELL CLEARANCE DISTANCES

WELL LOCATION, HOW TO FIND

Note that clearance distances from any septic system component such as septic and particularly including the drainfield, leachfield, soakaway, soakbed, or other synonyms for sewage effluent disposal will vary additionally in some jurisdictions according to 8-1

- The soil type. Rocky or sandy soils require greater setback distances from well to septic

- The soil grade or slope and location of a water well that is down-slope from the septic system

Water well, Public
or
Drinking water surface water intake
    200 1500 OH10 200 -100 ?

Water well
[Non-Potable]

    50 100 OH10 50 - -
                
Cesspool / Seepage Pit Clearances and Specifications
Cesspools min. freeboard 2   -   - -6" CESSPOOLS
Minimum volume 500   -   - -1/2 day -
Separation from Surface Water Supply 150   -   - -100 -
Separation from private well or suction line 150   -   - -50 -
Separation from private well, bad sample             50-100  

Table Notes

  1. Distances for these onsite wastewater treatment components are given in feet to other site features unless otherwise stated (a few distances may be given in inches).
  2. These septic information tables give typical required clearances for septic tank, soil absorption system (SAS), etc. but you will see that different authorities may recommend different distances.
  3. Small residential sewage treatment plant clearance distances are typically the same as those given for septic tanks.
  4. These distances are for conventional onsite waste disposal systems which specify clearances presuming that effluent is being disposed-of after minimal treatment such as is received by a septic tank or cesspool. Advanced onsite wastewater treatment systems, such as those described by Jantrania and Gross (2006), permit substantial reduction in these clearances, depending on the level of treatment achieved.
  5. Crossings of subsoil drains, lakes, watercoruses, streams, wetlands, and dry culches may be permitted where pipelines are constructed of sufficient strength to contain flows under pressure, based on Colorado
  6. Drainfield clearance distances are typically measured as from the site feature to the nearest edge of the drainfield area or trench, soak-pit, soakaway bed, mound, or raised bed, depending on septic design type. "Septic Setbacks - minimum separation distances, Park County CO, retrieved 2016/03/31, original source: http://www.parkco.us/DocumentCenter/Home/View/348

    1. 200 ft. The distance of 200 feet shall be maintained where fractured or jointed bedrock is within 7 ft. of the surface unless the results of a sub surface soil and geological investigation conducted by a p ofessional geologist indicates that a lesser distance would not result in contamination of adjacent wells or aquifers. - [CO]
    2. Add 8 ft. additional distance for each 100 gallons per day design flow over 1000 gallons per day as specified in the table unless it can be demonstrated by a professional engineer or geologist that a mechanical or natural barrier will prevent contamination. [CO]
    3. Crossings may be permitted where pipelines are constructed of sufficient strength to contain flows under pressure. [CO]
    4. The minimum distance required between wells and leach fields in subdivisions and all other developments, platted after January 1, 1997, shall be 200 feet. [CO]
  7. Abbreviations: 

    SAS = Soil Absorption System - Leach Field etc.

    UPC = Uniform Plumbing Code
  8. Sources of example septic setback & clearance distances, codes, citations, authorities
    1. CO = Colorado septic setbacks, see "Septic Setbacks - minimum separation distainces, Park County CO, retrieved 2016/03/31, original source: http://www.parkco.us/DocumentCenter/Home/View/348
    2. EPA references above and for other EPA information see WATER WELL CONSTRUCTION & MAINTENANCE [Details to Help Avoid Well Water Contamination] US EPA
    3. Mass.Title5 = Massachusetts Title 5 Septic Code
    4. FL = Florida septic component clearances table, also see Florida 64E-6.005 Location and Installation. (2013)
    5. General or "typical" septic component clearance distances are based on the CO information source where available
    6. MA = Massachusetts septic component clearances table
    7. MO = Missouri septic component clearances table - Missouri distances and septic lagoon system clearances to other site features University of Missouri extension lagoon web page muextension.missouri.edu/explore/envqual/wq0402.htm
    8. NY = New York State septic component clearances table
      New York State Department of Health, "APPENDIX 75-A WASTEWATER TREATMENT STANDARDS - INDIVIDUAL HOUSEHOLD SYSTEMS", [PDF] (2010) New York State Department of Health, 3 February 2010, retrieved 3/1/2010, original source: https://www.health.ny.gov/regulations/nycrr/title_10/part_75/appendix_75-a.htm

      New York State APPENDIX 75-A WASTEWATER TREATMENT STANDARDS - RESIDENTIAL ONSITE SYSTEMS, [PDF] (2016) retrieved 2017/12/09, original source: https://www.health.ny.gov/environmental/water/drinking/docs/appendix_75a.pdf

      Unofficial compliation of codes, rules and regulations of the state of New york title 10. Departmnet of health. Chapter ii. Part 75. Standards for Individual onsite water supply and individual onsite wastewater Treatment systems. Appendix 75-a.

    9. US HUD -1 Distance from source of pollution - proposed construction, US Dept. of Housing and Urban Development, FHA, Local acceptable standard No. 3, June 18, 1992, Ref. Hud Handbook 4910.1 Chg 1, Appendix K, Pg K-27
    10. Ohio Septic Code 3701-29-20 SEPTAGE & SEWAGE MANAGEMENT, retrieved 2017/10/20 original source: http://www.odh.ohio.gov/ -/media/ODH/ASSETS/ Files/rules/final/3701 -20-TO--29/3701-29/ 2015-0101/3701-29-20-N.pdf?la=en

Readers will find more details about septic system clearances and issues at NEIGHBORING SEPTIC SYSTEM PROBLEMS.

Below we provide additonal septic system component clearance distances

Table 2 Advanced or Special Septic System Component Clearance Distances (in feet) from Wells, Buildings, & Other Site Features

Site Feature / Component
(below)

Septic Holding Tank / Vault Lagoon
Distance

 LAGOON SEPTIC
Lined Evap/Trans
or
Lined
Pond
Advanced
Treatment
or
Greywater
System
Other Sanitary Code Specifications General

SEPTIC COMPONENT LOCATIONS
 

Authority or Model Code

General /
TYPICAL1
MO
Missouri
CO
Colorado
CO
Colorado
UPC
Uniform
Plumbing
Code
More
Information
Cistern 10 25 ft 25 25 - CISTERNS
Drainfield, Soakbed, Soil Absorption System above high
groundwater (water table)
  -     - SEPTIC DRAINFIELD SHAPE
Drainfield, Soil Absorption Sys. Minimum Area   -     150 -
Drainfield, SAS Other exc repair area   20 ft     - -
Dry gulch 10   10 256.2    
Embankment top or
Cuts >= 2ft hgt
  20 ft     - -
Intercept drain
up-slope
  10 ft     - -
Intercept drain
down-slope
  25 ft     - -
Lake, watercourse, stream, wetland
[high water line]
50 25 ft 50 506.2   -
Neighboring residence   200 ft     - -
Property Line   75 10 10   NEIGHBORING SEPTIC SYSTEM PROBLEMS
Septic Tank cover soil backfill
min" - max"
  -     - -
Surficial Sinkhole Edges   500     - -
Spring 50 100     - -
Structures to Septic Tank / Leach field
[Occupied]
  100 ft 15 20 10 ft -
Structures to Sewer Line
[Occupied]
           
Subsoil drain line 10   10 25    
Swimming Pool   100     - SEPTIC to POOL DISTANCE
Trees, large   -     - PLANTS & TREES OVER SEPTIC SYSTEMS
Water supply piping
[Potable]
10 10 10 25 - -
Water Supply Piping
under suction
50 100     - -

Water well, Private
[Potable]

50 - 60 1006.2 -

WELL CLEARANCE DISTANCES

WELL LOCATION, HOW TO FIND
Water well, Public   300     -

Water well
[Non-Potable]

  -     -
    WETLAND SEPTIC SYSTEMS        
Cesspool or Seepage Pit Clearances and Specifications
Cesspools min. freeboard 2 -     - CESSPOOLS
Minimum volume   -     - -
Separation from Surface Water Supply 150 -     - -
Separation from private well 150 -     - -
Separation from private well, bad sample            

Table Notes

  1. Distances for these onsite wastewater treatment components are given in feet to other site features unless otherwise stated (a few distances may be given in inches).
  2. These septic information tables give typical required clearances for septic tank, soil absorption system (SAS), etc. but you will see that different authorities may recommend different distances.
  3. Small residential sewage treatment plant clearance distances are typically the same as those given for septic tanks.
  4. These distances are for conventional onsite waste disposal systems which specify clearances presuming that effluent is being disposed-of after minimal treatment such as is received by a septic tank or cesspool. Advanced onsite wastewater treatment systems, such as those described by Jantrania and Gross (2006), permit substantial reduction in these clearances, depending on the level of treatment achieved.
  5. Crossings of subsoil drains, lakes, watercoruses, streams, wetlands, and dry culches may be permitted where pipelines are constructed of sufficient strength to contain flows under pressure, based on Colorado
  6. Drainfield clearance distances are typically measured as from the site feature to the nearest edge of the drainfield area or trench, soak-pit, soakaway bed, mound, or raised bed, depending on septic design type. "Septic Setbacks - minimum separation distances, Park County CO, retrieved 2016/03/31, original source: http://www.parkco.us/DocumentCenter/Home/View/348
    1. 200 ft. The distance of 200 feet shall be maintained where fractured or jointed bedrock is within 7 ft. of the surface unless the results of a sub surface soil and geological investigation conducted by a p ofessional geologist indicates that a lesser distance would not result in contamination of adjacent wells or aquifers. - [CO]
    2. Add 8 ft. additional distance for each 100 gallons per day design flow over 1000 gallons per day as specified in the table unless it can be demonstrated by a professional engineer or geologist that a mechanical or natural barrier will prevent contamination. [CO]
    3. Crossings may be permitted where pipelines are constructed of sufficient strength to contain flows under pressure. [CO]
    4. The minimum distance required between wells and leach fields in subdivisions and all other developments, platted after January 1, 1997, shall be 200 feet. [CO]
  7. Sources of example septic setback & clearance distances, codes, citations, authorities
    1. CA = California septic system codes including this model: GLENN COUNTY CALIFORNIA SEWAGE DISPOSAL CODE [PDF] - this is a 2.3MB PDF file retrieved 2017/05/08, original source https://www.countyofglenn.net/sites/default/files/Environmental_Health/SewageDisposalRegulations.pdf
    2. CO = Colorado septic setbacks, see "Septic Setbacks - minimum separation distainces, Park County CO, retrieved 2016/03/31, original source: http://www.parkco.us/DocumentCenter/Home/View/348
    3. EPA references above and for other EPA information see WATER WELL CONSTRUCTION & MAINTENANCE [Details to Help Avoid Well Water Contamination] US EPA
    4. Mass.Title5 = Massachusetts Title 5 Septic Code
    5. FL = Florida septic component clearances table, also see Florida 64E-6.005 Location and Installation. (2013)
    6. General or "typical" septic component clearance distances are based on the CO information source where available
    7. MA = Massachusetts septic component clearances table
    8. MO = Missouri septic component clearances table - Missouri distances and septic lagoon system clearances to other site features University of Missouri extension lagoon web page muextension.missouri.edu/explore/envqual/wq0402.htm
    9. NY = New York State septic component clearances table
      New York State Department of Health, "APPENDIX 75-A WASTEWATER TREATMENT STANDARDS - INDIVIDUAL HOUSEHOLD SYSTEMS", [PDF] New York State Department of Health, 3 February 2010, retrieved 3/1/2010, original source: https://www.health.ny.gov/regulations/nycrr/title_10/part_75/appendix_75-a.htm

      See additional notes about New York Septic System clearance distances in TABLE 4 CESSPOOL OR SEEPAGE PIT, RAISED / MOUND SEPTIC, SAND FILTER SEPTIC SPECIAL CLEARANCE DISTANCES
    10. US HUD -1 Distance from source of pollution - proposed construction, US Dept. of Housing and Urban Development, FHA, Local acceptable standard No. 3, June 18, 1992, Ref. Hud Handbook 4910.1 Chg 1, Appendix K, Pg K-27
    11. NORTH CAROLINA SEPTIC SETBACKS & CODE [PDF] retrieved 2018/03/17, original source: http://www.alamance-nc.com/envhealth/wp-content/uploads/sites/9/2013/10/SepticRulesCompleteEff10012011.pdf
      In this document see 15A NCAC 18A .1950 LOCATION OF SANITARY SEWAGE SYSTEMS

      CONVENTIONAL SEPTIC SYSTEMS in NORTH CAROLINA
      [PDF] Rule .1955 15A NCAC 18A .1900 Laws and Rules for Sewage Treatment and Disposal Systems, North Carolina Department of Public Health, retriefed 2018/03/17, original source: http://ehs.ncpublichealth.com/oet/docs/cit/oswpmod/oswt/C-ComponentsofConventionalSystem.pdf
      NOTICE: this is a presentation and does not include actual North Carolina septic code specifications, setbacks, distances.
      Also see https://content.ces.ncsu.edu/septic-systems-and-their-maintenance that in turn cites
      Mancl, K.M. 1984. Journal of Environmental Engineering, Vol. 110(1):283–285 and omits North Carolina septic code details.

      The below listed minimum separation distances as stipulated in North Carolina General Statutes 130A-335 (e), (f), are the most commonly used in planning for a home or small business.
      North Carolina Septic Tank Clearance distances:

      . septic tanks cannot be placed where there may be flooding every 10 years or less, unless the septic tank is watertight, anchored, and storm-water-entry-proof

      . at least 5 ft. from any building foundation

      . at least 10 feet away from property lines, water lines, and the up-slope portion of drainage systems..

      . at least 15 feet between septic tanks and basements, embankments, drainage system side-slopes, and swimming pools.

      . at least 25 ft. from property line

      . at least 25 feet setback for groundwater lowering ditches and devices, and the down-slope of drainage systems

      . at least 50 feet from any lake or pond

      . at least 100 feet away from private or public water supplies, streams, and reservoir.

Readers will find more details about septic system clearances and issues at NEIGHBORING SEPTIC SYSTEM PROBLEMS.

...

Table 3 Septic Component Clearance Distances to a Water Well According to Soil Type & Septic System Type

Soil Conditions 1 Depth from SAS Bottom to Groundwater Seasonal High Level 2
Septic Filter Trench Type & Distances to Water Well in Feet
Comments
TYPE I
Gravity-fed @ Normal Loading 3
TYPE II
Pressure-Dosed @ Normal Loading 3
TYPE III Pressure-Dosed @ Low-Loading 4
Very coarse gravelly soil < 5% Fines 4 to 5 ft. Not Allowed 200 ft. 150 ft. Soil properties in other geographic locations and in other sewage code jurisdictions will differ and may have different allowable septic system clearance distances than our examples given here.
> 5 ft to 10 ft 200 ft. 150 ft. 100 ft.
> 10 ft. 150 ft. 100 ft. 100 ft.
Coarse sandy soil, 5 to 15% Fines 4 to 5 ft. 200 ft. 150 ft. 100 ft.
> 5 ft to 10 ft 150 ft. 100 ft. 100 ft.
> 10 ft. 100 ft. 100 ft. 100 ft.

Notes & Sources of Example Septic System Codes & Specifications

  1. Here "soil" is defined as the "predominant" soil between the bottom of the trench (rock bed) and the soil must be both well-graded and having at least 40% of the soil passing a #4 sieve test (5mm sieve test).
  2. These distances are from bottom of the soil absorption system trench to the top of seasonal high groundwater table (see also Massachusetts Title 5 Septic Code). Any septic effluent disposal or absorption field that is seasonally flooded cannot work and cannot meet these specifications.
  3. "Normal septic system loading" rate is defined as a soil application rate of effluent at 1.0 gallons per day per linear foot of trench along the bottom area of the trench.
  4. "Low septic system loading" rate is defined as a soil application rate of sewage effluent at 0.5 gallons per day per linear foot of trench along the bottom area of the trench.

...

Table 4 Cesspool or Seepage Pit, Raised / Mound Septic, Sand Filter Septic Special Clearance Distances

Clearance
Distances For
Depth of System
Bottom to
Groundwater
Seasonal
High Level 1
Well or
Suction Line (e)(g)
Stream
Watercourse (b)
or Lake
Dwelling Property Line
Seepage Pit 3 ft. 150 ft. 100 ft. 20 ft. 10 ft.
Raised or Mound Septic   100 100 20 10
Intermittent Sand Filter Septic   100 100 20 10
Non-Waterborne System, Offsite Discharge   50 50 20 10
Non-Waterborne System, Onsite Discharge   100 50 20 10

Notes & Sources of Example Septic System Codes & Specifications

  1. NY = New York State septic component clearances table, Table 2, "Separation Distances from Wastewater System Components (in Feet)"

    New York State Department of Health, "APPENDIX 75-A WASTEWATER TREATMENT STANDARDS - INDIVIDUAL HOUSEHOLD SYSTEMS", [PDF] New York State Department of Health, 3 February 2010, retrieved 3/1/2010, original source: https://www.health.ny.gov/regulations/nycrr/title_10/part_75/appendix_75-a.htm

NOTES:

(a) When wastewater treatment systems are located upgrade and in the direct path of surface water drainage to a well, the closest part of the treatment system shall be at least 200 feet away from the well.

(b) Mean high water mark.

(c) For all systems involving the placement of fill material, separation distances are measured from the toe of the slope of the fill.

(d) Separation distances shall also be measured from the edge of the designated additional usable area as described in Section 75-A.4 (a)(5).

(e) The closest part of the wastewater treatment system shall be located at least 10 feet from any water service line (e.g. public water supply main, public water service line or residential well water service line).

(f) When sand filters are designed to be watertight and collect all effluent, the separation distance can be reduced to 50 feet.

(g) The listed water well separation distances from contaminant sources shall be increased by 50% whenever aquifer water enters the water well at less than 50-feet below grade. If a 50% increase cannot be achieved, then the greatest possible increase in separation distance shall be provided with such additional measures as needed to prevent contamination.

...


Continue reading at SEPTIC COMPONENT LOCATIONS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see SEPTIC CLEARANCE DISTANCE FAQs - questions & answers posted originally on this page.

Or see WELL CLEARANCE DISTANCES for required distances between wells and septic systems and other site features,

or if you can't find the well, see WELL LOCATION, HOW TO FIND

Or see this Septic component clearance & setback

Article Series

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CLEARANCE DISTANCES, SEPTIC SYSTEM at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC SYSTEMS

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